The Red Bomb chronicles Russia’s staggering transformation from lagging also-ran into nuclear superpower, as the USA and USSR battled it out for possession of the ultimate weapon.

By the time the Stalinist regime gives way to the era of Khrushchev, Russia and its rival are almost neck and neck. One war may be over, but another is just beginning. As rivalry deepens into outright hostility, can the quest to produce the ultimate atom bomb really be explained “in the name of peace”?

As the race accelerates, simple bomb tests are replaced by full-scale battle exercises and the spectre of nuclear war looms ever closer. The Soviets are plundering Czechoslovakian mines for their rich uranium reserves, and Russia upgrades its nuclear facilities, making Arzamas-16 and Semipalatinsk-21 into model cities for nuclear scientists and their families – furnished with dream homes, luxury shops and good schools (though the cities are untraceable on the map, and their inhabitants have no address). Archive footage of an imitation battle gives a hint of the war that never was – though most of the “sacrificies” are sheep and horses, stationed in the trenches in the name of military research. The Red Army evacuate farmers out of the chosen patch of countryside, allowing them to return a few days later, with nuclear dust still hanging in the air. (In the ensuing years, the local hospital saw a huge increase in tumour patients – a trend that the government did its utmost to conceal.)

As veterans revisit the scenes of their former labours – now snow-covered concrete shells, green meadows or deserted plains – their tales of noise, smoke and indescribable heat are hard to imagine. Russia’s first nuclear bomber describes the view – and the terrible shocks – from the cockpit. A soldier explores the ruins of the houses he built for the purpose of destruction. Former political prisoners from the Czech mines reunite and re-enact the gulag chain-gang march.

This final episode addresses the legacy of the Red Bomb, and the steady stream of scientists who became disenchanted with the project after seeing the potential devastation it could cause.